1Department of Anesthesiology and Pain Medicine, Seoul National University Bundang Hospital, Seongnam 463707, Republic of Korea2School of Life Science, Gwangju Institute of Science and Technology, Gwangju 500712, Republic of Korea3Laboratory of Veterinary Anatomy, College of Veterinary Medicine, Konkuk University, Seoul 143701, Republic of Korea4Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul 110744, Republic of Korea

Received 6 March 2014; Revised 14 August 2014; Accepted 25 August 2014; Published 16 September 2014